LearnSixSigm
In this Article
In this article you will learn…
- What SMED means and where it comes from.
- What it can do to improve efficiency and throughput.
- How to apply SMED through a simple real world example.
What Does SMED Mean?
SMED — Single Minute Exchange of Die, or simply put, it's the Lean concept of fast changeover.
Originally named by a Toyota engineer Shigeo Shingo for his goal to achieve a single minute exchange of tooling in an auto plant. His actual target was anything under 10 minutes, where previously changeover would take hours.
What Can It Do?
With SMED the gains in time and efficiency can be dramatic. These gains are likely proportional to the effort invested in improvement.
It’s all about cutting the changeover time from one process setup to a new one. This can dramatically cut the cycle time for a customer or significantly improve the utilisation and efficiency for equipment.
For example, take the last time you had a new tyre fitted. How long did it take? Twenty minutes or more? A Formula 1 pit crew can change all four tyres in 2 seconds. That’s about the best SMED you can find.
Amongst Lean professionals, Formula 1 pit crews are heroes and provide the ultimate benchmark for SMED.
How to Apply SMED — An Example
The Budget Airline
An example most of us can be familiar with. They have a clear incentive to shorten the time spent on the ground by saving time on aeroplane turnaround, maximising their productive time carrying passengers. It could even allow an extra flight per day.
To achieve the airline’s goal of, say, a 25 minute turnaround, they should consider the many tasks to complete in this time. Not just the cabin tasks that we see as passengers, but also the ground handling, refuelling, maintenance, safety inspections, crew change, etc.
We can then separate these tasks into several independent, parallel work streams that must be completed in the time allowed.
Let’s understand how an airline might go about this to explore how we could use SMED to improve our own changeovers. We will consider only the cabin tasks that most of us are familiar with, just to keep this simple.
Step 1 — Set the Goal and Scope
There is no value in having the cabin loaded, doors closed and crew ready to go if the ground handling tasks like refuelling are unfinished, so a common goal should be agreed upon.
- Goal:
- 25 minutes — Doors Open to Doors Closed
- Scope:
- Passenger Cabin Tasks for Cabin Crew
Step 2 — List the Required Tasks
For simplicity let's list the obvious and visible tasks for this example:
- Unload the passengers
- Collect the trash from the cabin seating area
- Clean the seats and tidy the magazines and safety info
- Clean the cabin floor
- Clean the toilets
- Clean the kitchen
- Unload and restock the kitchen
- Prepare the kitchen for service
- Load the new passengers
Step 3 — Divide Tasks into "External" and "Internal"
Next identify the tasks that can be completed externally to the changeover time. These tasks can be done before landing or after take off. They don’t have to be done while the aircraft is on the ground, with the doors open or seats empty.
External Tasks
- Collect the trash from the cabin seating area
- Clean the toilets
- Clean the kitchen
- Prepare the kitchen for service
Internal Tasks
- Unload the passengers
- Clean the seats and tidy the magazines and safety info
- Clean the cabin floor
- Unload and restock the kitchen
- Load the new passengers
Step 4 — Plan and Revise the Internal Tasks
These are the tasks critical to achieving the goal and this is where detailed planning and practice is key to success.
First breakdown the tasks and extract any elements that can be made external. Next execute internal tasks in parallel rather than sequential wherever possible. Time each task execution then plan and practice to streamline the time taken as much as possible.
Document and practice the execution of all tasks to follow a Standard Operating Procedure, so everyone can achieve the same performance. It may be necessary to use better equipment with faster operation and cycle time or different material specifications to allow faster processing, e.g. leather seats for faster cleaning.
Compare the achieved practice with the original goal and the achievement of the other parallel groups of activities — such as ground handling, refuelling, etc. These are likely managed by other teams and may create a spirit of healthy competition.
Set goals for each team to break down the tasks and focus on making incremental gains until the goal is met.
Set up a monitoring and data collection mechanism to record successes and analyse failures. Publish data, recognize and reward achievement.
Step 5 — Schedule the External Tasks
These are less critical but benefit from a Standard Operating Procedure. In our budget airline the seat belt signs are switched on 20 minutes before landing. Not because it is dangerous for passengers but because the crew need to get on with executing their external tasks in preparation for a speedy turnaround.
As much preparation as possible should be done before changeover. These tasks may also be scheduled after the changeover if this does not conflict with running the process. For the airline, preparing and stocking the kitchen, the trolleys and getting ready for service would be after take off.
